Risk of Asthma in Young Adults Who Were Born Preterm: A Swedish National Cohort Study

This is the first study with sufficient statistical power to evaluate the risk of asthma beyond adolescence in individuals who were born extremely preterm. The results suggest that extreme preterm birth (23–27 weeks' gestation), but not later preterm birth, is associated with an increased risk of asthma at least into young adulthood.

Casey Crump, MD, PhD,a Marilyn A. Winkleby, PhD,b Jan Sundquist, MD, PhD,b,c and Kristina Sundquist, MD, PhDc


Asthma is a chronic lung disorder that causes swelling and inflammation in the lungs and consequently narrowing of the airways. It is typically diagnosed in childhood; however it can develop at any age. When asthma symptoms appear in adults, it is known as adult-onset asthma. In adults, asthma symptoms are typically persistent, unlike in children where symptoms are mostly intermittent.

Symptoms of adult-onset asthma may include:

  • wheezing
  • coughing
  • congestion
  • mucus secretion in the airways
  • trouble sleeping
  • chest pain
  • pressure in the chest
  • shortness of breath after physical activity
  • delayed recovery from a respiratory infection eg flu or cold

Studies have found that extreme prematurity (23 to 27 weeks’ gestation) can be associated with an increased risk of being prescribed asthma medication in young adulthood, compared to those born full term. While later prematurity does not appear to carry the same risks.

With suitable planning and preparation, the frequency of asthma attacks can be controlled with daily treatment. Avoiding triggers such as smoke, pollen, pets, foods, changes in weather and respiratory illnesses can help minimize asthma flare ups.


The recognition of extreme prematurity as a possible risk factor for asthma in later life should always be considered. Doctors should be encouraged to gain a full medical history of an adult experiencing asthmatic symptoms and patients should be urged to inform their doctors of their prematurity when being seen for respiratory issues. As adults who were born premature are now living longer, therefore it is important that health professionals consider the affect that the early birth may have on the patient’s long-term health.

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Disclaimer: This publication by Miracle Babies Foundation is intended solely for general education and assistance and it is it is not medical advice or a healthcare recommendation. It should not be used for the purpose of medical diagnosis or treatment for any individual condition. This publication has been developed by our Parent Advisory Team (all who are parents of premature and sick babies) and has been reviewed and approved by a Clinical Advisory Team. This publication is not a substitute for professional medical advice. Miracle Babies Foundation recommends that professional medical advice and services be sought out from a qualified healthcare provider familiar with your personal circumstances.To the extent permitted by law, Miracle Babies Foundation excludes and disclaims any liability of any kind (directly or indirectly arising) to any reader of this publication who acts or does not act in reliance wholly or partly on the content of this general publication. If you would like to provide any feedback on the information please email [email protected].